The invention is in the field of packaging machines and relates to a band delivery method and apparatus having a band forward store and a band return store.
Metal or plastic bands, tapes, ribbons, strips and belts are frequently used as the encircling material for wrapping or encircling products or goods. The product to be packaged, e.g. a cardboard box or a bundle of magazines, newspapers, etc., is brought into the packaging position, is encircled by the band and is subsequently e.g. conveyed away for dispatch or shipping. Frequently the product is also covered crosswise by a band.
Numerous different apparatuses are known, which are used for the wrapping or encircling of products by means of bands. The externally visible operation of such encircling machines is often similar. The band is located in a band channel, which surrounds the product to be encircled. The band is stretched and jumps out of its position in the band channel and winds directly round the product being packaged. As a result of further stretching the product is closely wrapped and the band can then be connected (e.g. by bonding or welding), so that the encircling process is ended. If necessary, the product to be encircled or wrapped is turned and a second band loop is passed round it. For the next encircling process the band must be repositioned. When using such encircling machines in industrial production processes, the individual encircling processes are of a periodic nature and are generally repeated according to a system cycle.
In modern plants extremely high processing capacities are required, so that high demands are made on such encircling machines and band material as regards reliability, dynamics and operator friendliness. A considerable disadvantage of known machines of this type relates to the supply of the band. Known band delivery systems are extremely complex and therefore susceptible to faults. In order to be able to achieve high process speeds during encircling, frequently use is made of mechanically complicated band prestores, which require a manual threading and insertion of the band, besides the disadvantage of their slowness and fault susceptibility when changing empty band rolls. This manual changing of the bands leads to long process interruptions or requires a redundant system of encircling machines. Due to the complicated construction of such band delivery systems and due to the necessary redundancy, known systems are also relatively expensive. Conventional band delivery constructions do not provide adequate protection to the band, which leads to damage (bending, tearing, etc.) or weakens the band. Frequently the storage constructions used are very poor in this connection in that they bring about a completely uncontrolled storage of the band material. Another disadvantage of known constructions is that the individual band delivery systems are adapted to specific bands. Thus, it is generally not possible to change between different bands and it is necessary to accept disadvantages (reduced packing quality, lower speed, etc.), or alternatively the machine has to be reequipped.